Genus Deuterammina


Deuterammina Brönnimann, 1976


Type Description: The free trochospiral test is similar to Trochammina. Each chamber has 2 apertures, i.e. a primary interiomarginal, umbilical-extraumbilical opening and a secondary opening at the umbilical tip of the chamber and opening into the umbilicus. The primary apertures are covered in the course of growth whereas the secondary umbilical openings are visible and disposed in a low trochospire. The thin imperforate walls are agglutinated and devoid of secondary internal structure and do not form secondary subdivisions of the chamber.



Deuterammina rotaliformis (Heron-Allen & Earland, 1911)

Trochammina rotaliformis Heron-Allen & Earland, 1911, p. 309;  Cushman, 1920.

Trochammina rotaliformis Wright: Cushman and McCulloch, 1939, p. 107, pl.12, fig. 2.; Loeblich and Tappan, 1973; Brönnimann and Whittaker, 1983, pp. 350, 352; McGAnn, 2007, p. 64, pl. 9, fig. V;  Vázquez Riveiros and Paterson, 2008, fig. 4.6a, b.


Emended Type description – Test free, low dextral trochospiral spiral, subcircular in umbilical and spiral views and slightly lobate. In edge view, broadly domed on the spiral side through somewhat carinate. Umbilical depression star-shaped, open and deep with five branches. On spiral side, small subglobular proloculus followed by about 20 chambers arranged in at least three whorls with five chambers in the final whorl. Umbilically, shape of chambers broadly triangular; spirally, low and elongate. Two sets of apertures consisting of an interiomarginal extraumbilical primary opening of Trochammina-type and a secondary opening in a umbilical-sutural, posteriorly directed positon. Final primary opening devoid of any lip-like structure but secondary opening accompanied by distinct extensions which normally are well separated from the septal wall. Wall single layer and imperforate. Agglutinant of quartz flakes arranged in a mosaic patterns. Colour reddish brown. Maximum spiral and umbilical diameter 260 μm; minimum diameters 230 μm; thickness (axial height) 60 μm.


Remarks: This species is relatively abundant in Saratoga Passage, and Sinclair Inlet, central Sound.


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